The Variation of Coefficient of Friction With Temperature and Compaction Variables for Iron Powder Stearate-Lubricated Systems

Mallender, R. F.; Dangerfield, C. J.; Coleman, D. S.

doi:10.1179/pom.17.34.1974.003

Cited by 17 publications

(5 citation statements)

References 4 publications

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“…At higher pressures, 0?5% admixed lubricant appeared to provide nearly as much reduction in friction as the mix with 1% lubricant. This is in agreement with the findings of other authors (for example, Mallender et al, 1974). The overall effectiveness of lubrication is shown in Fig.…”

Section: Evolution Of Friction Under Different Loading Conditionssupporting

confidence: 93%

Friction measurement and lubrication in unloading and ejection stages in powder pressing cycle

Korachkin¹,

Gethin²,

Lewis³

et al. 2008

Powder Metallurgy

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The development of a floating die shear plate apparatus and its use to explore lubrication mechanisms (both admixed and die wall) and to assess the effectiveness of lubrication under a wide range of both compaction and normal loading conditions are described. The equipment allows the independent exploration of the effect of density and normal stress on the friction between compact and tool set surface. Tests were carried out using DistaloyAE, a zirconia target surface and Kenolube as lubricant (added or applied). A friction correlation that includes both density and normal stress effects and that reduces in response to both of these parameters was found. The results also suggest that the friction coefficient during ejection will be lower than that during compaction; at very high contact stresses, there is a likelihood that the lubrication regime will break down leading to galling. With regard to the friction mechanism, surface analysis using EDX did not detect the presence of lubricant on the compact surface; however, it did reveal two distinct pore types, a 'dark' one having a higher than average level of carbon and a 'light' one having a higher than average level of nickel. Image and topographical measurement of compacts subjected to sliding against the target surface revealed significant differences. Both analyses suggested significant closure of open pores due to sliding with topographical analysis revealing remnants of pores under the deformed particles that make up the exterior of the compact surface. Results confirmed there is no noticeable benefit in increasing admixed lubricant content above 0?5%. Die wall lubricant was demonstrated to be very effective, achieving a reduction in friction of up to 58% for unlubricated powder and up to 27% for powder containing 0?5% admixed lubricant. This was achieved for a lubricant film of typical thickness 5-20 mm.

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Section: Evolution Of Friction Under Different Loading Conditionssupporting

confidence: 93%

Friction measurement and lubrication in unloading and ejection stages in powder pressing cycle

Korachkin¹,

Gethin²,

Lewis³

et al. 2008

Powder Metallurgy

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“…Experimental studies indicate that friction depends on several factors including: contact pressure, local powder density, sliding velocity, sliding distance, temperature, and wall roughness. (Pavier and Doremus, 1997;Mallender et al, 1974;Ernst and Barnekow 1994;Mosbah et al, 1997;Wikman et al, 1997;Roure et al, 1999). In Section 6.2, we adopt the instrumented die method and present a number of case studies below where the friction coefficient is dependent on contact pressure and die wall condition.…”

Section: Friction Between Powder and Toolingmentioning

confidence: 99%

Modelling Powder Compaction

Sinka

2007

KONA

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Die compaction of powders is a process which involves filling a die with powder, compression of the powder using rigid punches to form a dense compact, and ejection from the die. The choice of powder composition and selection of process parameters determine the microstructure and final properties of the compacts. The practical issues in the powder-forming industries (powder metallurgy, ceramics, hard metals, pharmaceuticals, detergents, etc.)

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“…In general, the admixed lubrication is more productive and economical process than die-wall lubrication in powder metallurgy (P/M) process. However, in admixed lubrication, residual lubricants between powder particles interfere with inter-particle diffusion during sintering process, resulting in deterioration of mechanical properties of sintered Al P/M alloys [2][3][4][5][6][7][8][9]. In the present study, a newly developed lubricant mixture is proposed to improve sintered properties of Al-Cu-Mg P/M alloy, and its de-lubrication behavior is investigated.…”

Section: Introductionmentioning

confidence: 99%

De-Lubrication Behavior Of Novel EBS Based Admixed Lubricant In Aluminum P/M Alloy

Seok

Kim³

et al. 2015

Archives of Metallurgy and Materials

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The objective of the present research is to develop a novel lubricant for Al-Cu-Mg P/M alloy and to address the effects of the lubricant and compaction pressure on sintered properties. A lubricant mixture consisting of Ethylene Bis Stearamide, Zn-Stearate, and fatty acid was newly developed in this study, and the de-lubrication behavior was compared with that of other commercial lubricants, such as Ethylene Bis Stearamide, Zn-Stearate, and Al-Stearate. Density and transverse rupture strength of sintered materials with each lubricant were examined, respectively. The microstructural analysis was conducted using optical microscope.

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The Variation of Coefficient of Friction With Temperature and Compaction Variables for Iron Powder Stearate-Lubricated Systems

Cited by 17 publications

References 4 publications

Friction measurement and lubrication in unloading and ejection stages in powder pressing cycle

Friction measurement and lubrication in unloading and ejection stages in powder pressing cycle

Modelling Powder Compaction

De-Lubrication Behavior Of Novel EBS Based Admixed Lubricant In Aluminum P/M Alloy

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